U.S. patent number 5,315,642 [Application Number 07/869,190] was granted by the patent office on 1994-05-24 for concurrent creation and transmission of text messages to multiple paging services.
This patent grant is currently assigned to Canamex Corporation. Invention is credited to Jorge D. Fernandez.
United States Patent |
5,315,642 |
Fernandez |
May 24, 1994 |
Concurrent creation and transmission of text messages to multiple
paging services
Abstract
A paging device sends text messages to pagers via paging
services observing different communication protocols. Communication
data is stored in random access memory and includes a service file
identifying telephone numbers and protocols associated with each
paging services and a pager file containing pager identification
codes. Operator message creation and automatic transmission occur
contemporaneously, coordinated with status fields in message
records. Each newly-created message is stored in a queue together
with control data identifying a paging service and pager and status
data indicating a "pending" status, namely, a requirement for
transmission of the message. The automatic transmission involves
repeated scanning of the queue for pending messages, programming a
modem according to the message's control data, and arranging
transmission to the relevant service. The status of messages
subject to transmission errors is automatically set to "rejected".
The operator can retrieve any message from queue, setting its
status from rejected to pending to reinitiate transmission or from
pending to cancelled to suppress transmission. Communication data
can also be transmitted to and received from an identical device in
a remote service center, to allow correction of faulty
communication data or reconfiguration to meet user
requirements.
Inventors: |
Fernandez; Jorge D.
(Willowdale, CA) |
Assignee: |
Canamex Corporation (Markham,
CA)
|
Family
ID: |
25675094 |
Appl.
No.: |
07/869,190 |
Filed: |
April 16, 1992 |
Current U.S.
Class: |
379/93.17;
340/7.31 |
Current CPC
Class: |
H04W
88/185 (20130101) |
Current International
Class: |
H04Q
7/10 (20060101); H04Q 7/06 (20060101); H04M
011/00 () |
Field of
Search: |
;379/52,93,96-99,57,63
;340/311.1,825.44 ;455/38.1,38.4 ;370/94.1,93 ;343/718 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Chan; Wing F.
Attorney, Agent or Firm: Waraksa; Mirek A.
Claims
I claim:
1. For a remotely-located device that transmits text messages with
a programmable modem over telephone lines to a paging service that
serves pagers and observes a particular communication protocol, the
device using communication data stored in storage means associated
with the device to communicate with the paging service and being
programmed to permit entry and editing of the communication data,
the communication data comprising at least paging service data
identifying the communication protocol of the paging service, a
method of reconfiguring the communication data of the
remotely-located device to correct transmission problems associated
with faulty communication data or to meet operator communication
requirements, the method comprising:
telephonically connecting the remotely-located device via its modem
with a device at the service center;
operating the remotely-located device to retrieve from its
associated storage means the communication data and to transmit the
retrieved communication data according to a predetermined
communication protocol via its modem over telephone lines to the
telephonically-connected service center device;
storing the received communication data in storage means associated
with the service center device;
reconfiguring the received communication data with the service
center device;
telephonically connecting the service centre device with the
remotely-located device after reconfiguring the received
communication data;
transmitting the reconfigured communication data from the service
centre device over telephone lines to the telephonically-connected
remotely-located device; and,
operating the remotely-located device to store the reconfigured
transmitted communication data in the storage means associated with
the remotely-located device for later use by the remotely-located
device for communication with the paging service.
2. The method of claim 1 in which:
the remotely-located device is programmed for operator recording of
the paging service data in a predetermined block of storage
locations of predetermined size at a predetermined location in the
storage means of the remotely-located device;
the service center device operates substantially identically to the
remotely-located device;
the retrieval and transmission of the paging service data from the
remotely-located device comprises sequentially retrieving and
transmitting the paging service data from the predetermined
location in the storage means of the remotely-located device;
the storing of the received paging service data by the service
center device comprises storing the received paging service data
sequentially in a block of storage locations at the same
predetermined location in the storage means of the service center
device;
the transmission of the reconfigured paging service data from the
service center device comprises sequentially retrieving and
transmitting the reconfigured paging service data from the
predetermined location in the storage means of the service center
device; and,
the storing of the reconfigured, transmitted paging service data by
the remotely-located device comprises storing the reconfigured,
transmitted paging service data sequentially in a block of storage
locations at the predetermined location in the storage means of the
remotely-located device.
3. A device for sending text messages destined for pagers over
telephone lines to a paging service serving the pagers,
comprising:
input means comprising a keyboard;
a display;
storage means for storing data in digital form;
a modem;
control means coupled to the input means, the display, the storage
means and the modem;
the control means comprising an operator-controlled mode of
operation and a concurrent automatic mode of operation, the control
means being programmed for the operator-controlled mode of
operation:
(a) to permit an operator with the input means to compose messages
on the display and to associate each of the composed messages with
any one of the pagers; and,
(b) to store each of the composed messages in a message queue in
the storage means together with transmission data identifying the
associated pager and status data associating a predetermined status
with the message, the predetermined status being one of a set of
predetermined statuses including a transmit status and a
transmitted status;
the control means being programmed for the automatic mode of
operation:
(d) to repeatedly scan the message queue to identify messages whose
status data indicates a transmit status;
(e) to transmit via the modem over the telephone lines to the
paging service each of the identified messages; and,
(f) to alter the status data of the identified messages to
associate therewith a transmitted status.
4. The device of claim 3 in which the control means are programmed
for the operator-controlled mode of operation to permit the
operator to view any one of the stored messages on the display and
to alter the status data of the stored message to associate a
different one of the predetermined statuses with the stored
message.
5. The device of claim 3 in which:
the control means are programmed to retrieve from the storage means
paging service data comprising a plurality of telephone numbers for
communication with the paging service; and,
the control means are programmed to control telephonic connection
of the programmed modem with the paging service by:
(1) selecting one of the plurality of telephone numbers;
(2) transmitting the selected telephone number with the programmed
modem over the telephone lines thereby to initiate telephonic
connection of the programmed modem to the paging service;
(3) detecting whether a busy signal is generated on the telephone
lines in response to transmission of the selected telephone
number;
(4) responsive to detection of the busy signal, decoupling the
modem from the telephone lines and selecting a different one of the
plurality of telephone numbers; and,
(5) repeating steps (1) through (4) for a predetermined number of
times and terminating the repeating of the steps if the programmed
modem connects telephonically to the paging service.
6. The device of claim 3 in which the control means are programmed
to retrieve from the storage means communication data comprising
paging service data identifying the communication protocol and at
least one telephone number of the paging service and comprising
pager data identifying data required by the paging service to
identify each of the pagers for communication therewith and in
which the control means have a predefined data-transmitting mode
and are programmed to respond to a predetermined command generated
by operator operation of the input means to assume the
data-transmitting mode, the control means being programmed for the
data-transmitting mode to:
control the input means and the display such that the operator can
with the input means specify a telephone number for a remote device
programmed to receive communication data stored in the storage
means;
control the modem to telephonically connect the modem over
telephone lines to the remote device;
retrieve the communication data from the storage means after
telephonic connection of the modem to the remote device; and,
transmit the communication data according to a predetermined
communication protocol over the telephone lines to the remote
device.
7. The device of claim 6 in which the control means have a
predefined data-receiving mode and are programmed to respond to a
predetermined command generated by operator operation of the input
means to assume the data-receiving mode, the control means being
programmed for the data-receiving mode to:
program the modem to receive communication data according to a
predetermined communication protocol from a remote device that
telephonically connects to the modem over telephone lines; and,
store the received communication data in the storage means for
retrieval by the control means in connection with the creation of
messages.
8. The device of claim 3 adapted to transfer communication data
stored in the storage means to and from a substantially identical
device, the device comprising a data transfer port for transferring
data to and from the substantially identical device, the control
means being programmed to:
respond to predetermined operator commands generated at the input
means by retrieving the communication data stored in the storage
means and transmitting the retrieved communication data in a
predetermined format to the data transfer port; and,
respond to predetermined operator commands generated at the input
means by receiving communication data in a predetermined format and
storing the received communication data in the storage means for
later retrieval by the control means in connection with the
creation of messages.
9. The device of claim 8 in which the control means are programmed
for the transmission of each of the messages to:
detect a message transmitted by the paging service to the device
indicating that any one of the messages has been rejected by the
paging service; and,
alter the status data of the rejected message to associate a
rejected status with the message thereby to suppress further
transmission of the message in the automatic mode of operation.
10. The device of claim 8 in which the control means are programmed
for the transmission of each of the messages to:
transmit a telephone number of the paging service up to a
predetermined number of times;
detect a busy signal on the telephone lines responsive to each
transmission of a telephone number of the paging service; and,
alter the status data of the message to associate a rejected status
with the message in response to detection of the busy signal the
predetermined number of times thereby to suppress further
transmission of the message in the automatic mode of operation.
11. A method of sending text messages destined for pagers with a
programmable modem over telephone lines to a plurality of paging
services serving the pagers and observing different communication
protocols, comprising:
storing communication data in digital form in a storage medium, the
communication data comprising paging service data identifying for
each of the paging services its communication protocol and at least
one telephone number for the paging service and comprising pager
data identifying for each of the pagers one of the paging services
serving the pager and data required by the one paging service to
identify the pager for communication therewith;
composing the messages with input means comprising a keyboard;
operating the input means in response to the stored communication
data to generate for each of the messages transmission control data
associating the message with a particular pager and the paging
service serving the particular pager;
storing each of the composed messages and its associated
transmission control data in digital form in a message queue in the
storage medium thereby creating a queue of messages associated with
different ones of the paging services;
transmitting the messages in the message queue to the associated
paging services, the transmission comprising repeatedly:
(a) selecting an untransmitted message in the message queue and
identifying from its associated stored transmission control data
the particular paging service associated with the selected
message;
(b) identifying among the messages in the message queue other
untransmitted messages for which the associated stored transmission
control data also identify the particular paging service;
(c) programming the modem for transmission to the particular paging
service in response to the transmission control data associated
with the selected message and the stored paging service data for
the particular paging service; and,
(d) communicating with the particular paging service via the
programmed modem to transfer the selected message and the other
identified messages in succession to the particular paging in a
single communication session.
12. The method of claim 11 comprising an operator-controlled mode
of operation and a concurrent automatic mode of operation:
the operator-controlled mode of operation comprising the creation
and storage of the messages, the creation and storage of the
messages including storing status data together with each of the
composed messages indicating a transmit status;
the automatic mode of operation comprising the transmission of the
messages, the transmission comprising altering the status data of
each of the transmitted messages to indicate a transmitted
status.
13. The method of claim 12 in which the operator-controlled mode of
operation comprises displaying on the display messages whose status
data indicates a transmitted status and modifying the stored status
data of the displayed messages to indicate a transmit status
thereby to reinitiate transmission of the messages in the automatic
mode of operation.
14. The method of claim 11 comprising the preliminary step of:
coupling the device through a data transfer port to a storage
device containing the communication data;
operating the device to retrieve the communication data from the
storage device; and,
storing the communication data retrieved from the storage device in
the storage medium for retrieval during the creation of the
messages.
15. The method of claim 11 in which the paging service data
comprises a plurality of telephone numbers for communication with a
particular one of the paging services, the communication with the
particular paging service comprising:
(1) selecting one of the plurality of telephone numbers;
(2) transmitting the selected telephone number with the programmed
modem over the telephone lines thereby to initiate telephonic
connection of the programmed modem to the particular paging
service;
(3) detecting whether a busy signal is generated on the telephone
lines in response to transmission of the selected telephone
number;
(4) responsive to detection of the busy signal, decoupling the
modem from the telephone lines and selecting a different one of the
plurality of telephone numbers;
(5) repeating steps (1) through (4) for a predetermined number of
times and terminating the repeating of the steps if the programmed
modem connects telephonically to the particular paging service.
16. The method of claim 11 comprising the preliminary steps of:
programming the modem for telephonic communication with a remote
device according to a predetermined communication protocol;
telephonically connecting the modem with the remote device over
telephone lines;
receiving at least part of the communication data from the remote
device over the telephone lines; and,
storing the received communication data in the storage medium for
retrieval during the creation of the messages.
Description
FIELD OF THE INVENTION
The invention relates generally to transmission of text messages
(alphanumeric and other conventional characters) to pagers. More
specifically, it relates to devices and methods for relaying such
messages through paging services observing different communication
protocols, transmission of message concurrently with operator
creation and handling of messages, and to a variety of other
enhancements to prior practices.
BACKGROUND OF THE INVENTION
A particular text-transmitting device has dominated the paging
industry. That is the "Alphamate" distributed by Motorola Company.
The Alphamate is a microprocessor-based device that stores pager
data and messages in a random access memory. The pager data
consists of the initials of pager users and the identification
codes required by an associated paging service to communicate with
the pagers. In a message-creating mode, an operator can compose a
message on a display using a keyboard and can specify a pager for
which the message is intended. The message together with the pager
identification code is then added to a transmission queue of like
messages in memory. In an entirely separate message-transmitting
mode, the microprocessor dials a particular paging service through
a modem and transmits all message in succession to the paging
service. The messages are then immediately cleared from memory
(except for the last-transmitted message), and the message-creating
mode can be resumed.
There are several significant limitations to the prior device. It
is adapted to communicate only with a single paging service.
Unfortunately, paging services observe different communication
protocols, including different baud rates, parity, word lengths,
and maximum message lengths. A separate device would be required to
handle communications with each paging service and would require
connection to a separate telephone line. Also, the prior device
does not allow concurrent message creation and transmission. While
the device is in its message-transmitting mode, the operator is
unable to compose and enter messages. Also, the transmission
function of the prior device has significant limitations. The
device essentially transmits the telephone number of the paging
service, and after a period of time transmits its messages in
succession. That occurs even when a busy signal is encountered,
losing messages. Also retransmission of messages received garbled
is not possible, except for the last message that has been
transmitted and remains stored.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a device for sending text
messages to paging services observing different communication
protocols. The device includes input means comprising a keyboard, a
display, storage means for storing data in digital form, and a
programmable modem. Control means, such as a microprocessor, are
coupled to the input means, the display, the storage means and the
modem. The control means are programmed to retrieve from the
storage means certain communication data. The communication data
comprises paging service data identifying the communication
protocol observed by each paging service (including necessary modem
configuration data) and at least one telephone number. It also
comprises pager data identifying the paging service serving each of
the pagers and the data required by the paging service to identify
the pager for communication.
The control means control creation of a message essentially as
follows. The operator is permitted to compose the message on the
display and specify a particular pager. Transmission control data
are generated in response to the user's specification of the
particular pager and in response to the pager data associated with
the particular pager. The transmission control data associates the
message with the particular pager and the paging service serving
the particular pager. The message is stored together with the
transmission control data in a message queue maintained in the
storage means.
The control means transmit each of the messages in the queue
essentially as follows. The control means program the modem for
communication with the paging service associated with the message.
The programming of the modem is done in response to the
transmission control data associated with the message, which
identifies the associated paging service, and in response to the
communication data in the storage means, which contains information
regarding the communication protocol observed by the paging
service. The controls means then communicate with the associated
paging service to transfer both the message and data identifying
the pager associated with the message.
The control means preferably provide an operator-controlled mode of
operation and a concurrent automatic mode of operation controlling
the transmission of messages. A conventional multitasking processor
or multiple processors may be used. For the operator-controlled
mode of operation, the control means store status data together
with each of the composed messages indicating the current status of
the message. The current status is one of a set of predetermined
statuses including at least a transmit status (a requirement for
transmission of a message) and a transmitted status (indicating
that the message has be transmitted or that an attempt to transmit
has been made). The operator is permitted to view stored messages
on the display and to alter the status data of the stored messages,
including altering a transmitted status to a transmit status. The
control means are programmed for the automatic mode of operation to
continually scan the message queue to locate messages whose status
data indicates a transmit status, to transmit such messages via the
modem, and to alter the status data of each of the messages in
response to successful transmission of the message to identify a
transmitted status. If a message is later identified by a pager
user as having been received garbled, the operator can retrieve the
transmitted message and alter the status data to once again
indicate a transmit status, re-transmission being controlled by the
automatic mode of operation. Basically, message handling by the
operator and transmission functions are coordinated by entering and
altering status codes, allowing the two types of functions to occur
concurrently without conflict.
The control means are preferably programmed to optimize message
throughput. First, a message requiring transmission is selected,
preferably the earliest created message. The transmission control
data associated with the message are used to identify the
associated paging service, and the modem is programmed for
transmission to the particular paging service. A telephonic
connection is completed between the modem and the particular paging
service, and the selected message is transmitted. The order of the
message queue is not observed. Instead, the control means identify
other messages in the message queue whose transmission data
identify the same paging service. These messages are transmitted
during the single communication session involving transmission of
the selected message, rather than logging off and proceeding to the
next message in the message queue.
The device is preferably adapted to respond to busy signals in a
particular manner. Several telephone numbers may be stored for
communication with a particular paging services. The control means
are adapted to control telephonic connection of the programmed
modem with the particular service by selecting one of the telephone
numbers. The selected telephone number is transmitted with the
programmed modem over the telephone lines to initiate a telephonic
connection. The control means detect through the modem whether a
busy signal is generated on the telephone lines. In response to a
busy signal, the controls decouple the modem from the telephone
lines, and select a different telephone number for the particular
paging services. This procedure is repeated a predetermined number
of times and terminated if a telephonic connection is
completed.
Communication data must of course be entered into the device. That
can be done with conventional data entry routines. In the prior
art, only data regarding a single paging service was required, and
such data could be conveniently and reliably entered a single time
by a knowledgeable installer. However, the present device will
generally be configured to allow end-users to enter communication
data for various paging services. They may have little familiarity
with concepts of baud rate, parity, word length, and other aspects
of communication protocols. There is consequently a greater
likelihood of transmission problems owing to entry of faulty
communication data. As well, if communication data is updated or
reorganized only infrequently, the operator may not develop
significant comfort with relevant data entry procedures.
Accordingly, in another aspect, the control means have a
data-transmitting mode that is assumed in response to a
predetermined operator command. In the data-transmitting mode, the
control means are programmed to permit the user to specify a
telephone number for a device adapted to receive communication data
stored in the storage means and located, for example, at a service
center. The modem is then telephonically connected to the service
center device. The control means then retrieve the communication
data from the storage means, and transmit the communication data
according to a predetermined communication protocol to the service
center device over telephone lines. The communication data, once
received by the service center device, is "reconfigured"
(corrected, reorganized or augmented) to address failures in
communication attributable to faulty data entry or to meet user
communication needs. The control means are also adapted to assume a
data-receiving mode responsive to a predetermined command, in which
the control means program the modem to receive communication data
according to a predetermined communication protocol from the
service center device and then store the received communication
data for later retrieval in connection with the creation of
messages. The service center device is telephonically connected to
the user's device in the data-receiving mode, and the reconfigured
communication data is transmitted back to the user's device for
use.
Other aspects of the invention will be apparent from a description
below of a preferred embodiment and will be more specifically
defined in the appended claims.
DESCRIPTION OF THE DRAWINGS
The invention will be better understood with reference to drawings
in which:
FIG. 1 is a diagrammatic representation of the external appearance
of a paging device embodying the invention;
FIG. 2 is a diagrammatic representation of various ports and jacks
at the back of the paging device, indicating how it may be
connected to various external devices and lines;
FIG. 3 is a schematic representation of the device;
FIGS. 4-6 are schematic representations respectively of the
structures of service file records, pager records, and message
records maintained by the paging device;
FIG. 7 is a sequence of screen layouts for pager data entry;
FIG. 8 is sequence of screen layouts for entry of messages;
FIG. 9 is a sequence of screen layouts for entry of paging service
data;
FIG. 10 is a diagrammatic representation of a message queue, paging
services and pagers for which the messages are destined, and
various components of the paging device;
FIGS. 11a-11c are a flow chart indicating how transmission of
messages in the queue is regulated;
FIG. 12 is a sequence of screen layouts for viewing messages in
queue and modify certain status data associated with the
messages;
FIG. 13 schematically illustrates an arrangement for servicing the
paging device from a remote service center to reconfigure
communication data contained in the paging device;
FIG. 14 diagrammatically illustrates how pager and paging service
data files are located in memory, both in the paging device of FIG.
1 and the service center device;
FIG. 15 is a sequence of screen layouts for a data-receiving mode
of the paging device; and,
FIG. 16 is a sequence of screen layouts for a data-transmitting
mode of the paging device;
FIG. 17 is a flow chart illustrating the principal steps in the
transmission of communication data from the paging device of FIG. 1
to the service center; and,
FIG. 18 is a flow chart illustrating the principal steps in the
receipt of the transmitted communication data for reconfiguration
at the service center.
DESCRIPTION OF PREFERRED EMBODIMENT
Reference is made to FIGS. 1-3 which illustrate the various
components of a paging device 10 embodying the invention. The
device 10 comprises a housing 12 which contains a two-line liquid
crystal display 14 (LCD) and a keyboard 16 of conventional
construction. Several ports and jacks are mounted on the back of
the device 10. These include a DC power input jack 18 which can be
coupled by a standard AC/DC adaptor 20 to a AC power line. A
conventional printer port 22 permits the device 10 to be connected
to a printer. A standard RS-232 port 24 permits transfer of data to
and from external devices, such as a personal computer 26 (optional
connection shown in stippled outline) or through a null modem
adaptor 28 to the RS-232 port (not illustrated) of a substantially
identical paging device 30. A line jack 32 permits the device 10 to
be coupled in a conventional manner to a phone line or PBX, as at a
conventional wall jack 34. A telephone jack 36 permits a telephone
38 to be coupled to the same phone line or PBX when the device 10
is not otherwise communicating with paging services. This last
aspect of the paging device 10 is a conventional practice with many
devices adapted to connect to telephone lines 52 and will not be
described further.
The principal components of the paging device 10 are apparent in
FIG. 3. A microprocessor 40 controls the overall operation of the
device 10. It is programmed by software code contained in an
erasable programmable read only memory (EPROM) 42. Communication
data and messages are stored in static random access memory (SRAM)
44. A conventional programmable modem 46 is used to couple the
microprocessor 40 for telephonic communication with paging
services, such as the services diagrammatically illustrated in FIG.
10. The modem 46 contains a processor (not illustrated) immediately
controlling its operation in a conventional manner. A printer
driver 48 couples the microprocessor 40 in a conventional manner to
the printer port 22 to operate the printer. The device 10 may
comprise a battery-operated back-up power supply (not illustrated)
to preserve communication data and messages stored in SRAM 44 if
power line voltage is temporarily interrupted.
Communication data are stored as files in the SRAM 44, as indicated
in FIG. 14. These include a pager file and a paging service file.
The pager file contains records identifying individual pagers. The
service file contains records identifying particular paging
services and containing data respecting their communication
protocols.
Each record in the service file contains certain common fields, the
record structure being illustrated in FIG. 4. These include a name
field identifying the service, first and second telephone number
fields, first and second baud rate fields, a parity field, a word
length field, a message length field, and a sequence number field.
The name field will normally contain the name of the service as the
operator wishes to identify it. The telephone number fields contain
alternative telephone numbers for contacting the service. Paging
services often provide different baud rates associated with
different telephone numbers, and accordingly corresponding baud
rate fields are provided. A paging service will generally use
common parity and word lengths regardless of baud rates offered.
Accordingly, only single fields are provided to store the parity
and word parameters required for communication with the particular
service. The message length field contains the maximum length of
any message that the particular service will accept. The data in
these various fields will typically be entered by the operator
using specifications provided by a particular paging service. The
sequence number field is assigned a unique numeric value in a
conventional manner, by the microprocessor 40 during record
creation. That value is used to link pager records to particular
pager services records, effectively associating each pager with a
particular service. That value is also incorporated into messages
at the time of creation to associate each message with a particular
paging service. This permits later retrieval of paging service
communication data for appropriate programming of the modem 46.
The record structure of each record in the pager file is
illustrated in FIG. 5. Each record includes a name field, a service
field, and a pager ID field. The name field will normally contain
the name of the pager user, information more meaningful to an
operator than pager identification numbers. The service field
contains the unique sequence number of the paging service record of
the service associated with the pager. The pager ID field contains
the pager number which the pager service associates with the
pager.
The paging service and pager files are arranged in a particular
manner in memory. Blocks of SRAM 44 of fixed size are assigned to
each of the files, as illustrated in FIG. 14. Basically, a block A
of SRAM 44 at a predetermined starting address A stores the paging
service file. A block B of SRAM 44 at predetermined starting
address B stores the pager file. The ending addresses are fixed by
the size of the assigned memory blocks. The fields and records of
these files are assigned fixed lengths. The records are essentially
contiguous within the assigned memory blocks. Retrieval of records
by the microprocessor 40 involves scanning through the memory
blocks according to starting addresses, record lengths, and the
block sizes. Individual items of data are retrieved from individual
records by noting the predetermined field lengths. The records in
each of the files are maintained in alphabetic order according to
the relevant name field to simplify searching. The assignment of
fixed blocks at known addresses has bearing on how the paging
device 10 can be serviced remotely, a matter discussed more fully
below.
Entry and editing of pager data will be described with reference to
FIG. 7. The normal operating mode presented to the operator after
start-up is message creation. The operator can enter a command such
as "@Config". The operator is then presented with a screen
providing configuration options, such as setting the date and time
of the clock (not illustrated) associated with the microprocessor
40 or entering names (pager records). Upon entry of the numeric
code associated with the names option, the operator is presented
with a screen indicating the number of pagers recorded in the pager
file. The operator enters the first letters of the name of a pager
user, for example, as illustrated, "Jim Ram", and the
microprocessor 40 initiates a search for pager file records
satisfying the search criteria.
If no match is found, a data entry function is initiated. The
screen layout is modified to ask whether a new file record is to be
added. If the user types "Y" to confirm, a screen layout is
presented to request the first required data, namely, the paging
service that serves the individual's pager. A first paging service
is indicated, and the microprocessor 40 effectively allows the user
to scroll through the service file records by pressing previous and
next keys associated with the keyboard 16. Once the desired service
is displayed on the screen, the user can press the enter key of the
keyboard 16 to associate the new pager with the particular paging
service. The microprocessor 40 appropriately records the sequence
number of the selected paging service record in the corresponding
service field of the new pager file record. The microprocessor 40
then causes the next screen to be presented requesting the pager
user's identification number. The number to be entered is the
number assigned to the individual's pager by the particular paging
service, and upon entry the value is appropriately recorded.
If pager records are found that match the search criteria, a data
editing function is initiated. The operator is permitted to scroll
with next and previous keys through the selection of pager records
that have been located. Once a record is selected, the screen
layout is modified to indicate an edit function, which is initiated
by pressing the enter key. The microprocessor 40 can then step the
user through the screen layouts used to enter a new record,
displaying recorded values and allowing editing. Alternatively,
menu choices can be provided identifying the particular field to be
edited, and the operator can be directed immediately to a screen
layout presenting the current value of the particular field and
allowing editing of the field value.
Entry of paging service data will be described with reference to
the sequence of screen layouts in FIG. 9. In the initial screen
layout for message creation, the user enters a predetermined
command such as "@SERVICE". The microprocessor 40 then presents a
screen requesting the user to identify whether service file records
or general communication data is to be accessed. The microprocessor
40 then presents a screen identifying the number of paging service
records currently in SRAM 44, and the operator is permitted to
scroll to a desired paging service record with next and previous
keys. Alternatively, as illustrated, the operator can enter the
name of a paging service, for example, as illustrated, "USPAGE". By
entering a service name that the microprocessor 40 cannot locate,
as with entry of pager data, a screen layout is presented
requesting confirmation that a new service file record is to be
created. The microprocessor 40 then presents a series of screen
layout requesting a first telephone number for the new service. A
special character such as a comma may be added to the end of the
telephone number to indicate to the microprocessor 40 that a delay
of several seconds should be allowed before dialing the number,
essentially to obtain a dial tone. This accommodates use of the
paging device 10 through a PBX. The screen is then modified to
request entry of a baud rate, which at present is either 300 or
1200. The screen is then modified to request entry of a second
telephone number, and then a second baud rate. These can be left
blank if appropriate. A series of screens are then presented to
gather other communication data, namely, parity, word length, and
maximum message length. The new record now contains all
communication data required to program the modem 46 to observe the
communication protocols of the service. Editing of such records
proceeds in a manner analogous to that of pager records. IXO TAP
communication protocols govern other aspects of communication with
paging services and are preprogrammed in the EPROM 42 for retrieval
by the microprocessor 40.
General communication data can also be entered in a similar manner.
Comparable entry screens collect data to set the number of attempts
that should be made to connect to a paging service in response to
busy signals or failure to obtain a carrier, delay time for
detecting a carrier from the paging service, and delay time for
detecting a response from the paging service during handshaking. If
the specified delay periods are exceeded, a communication error is
assumed.
Deletion of a record in either the pager file or the service file
can be triggered by simply nulling the name field and pressing
enter with an appropriate request for confirmation. It is
desirable, however, to scan stored messages to ensure that deletion
is inhibited if data associated with an existing message would be
affected. Deletion should also be inhibited with respect to a
paging service record, if a pager record is associated with the
paging service record. That can be done in a conventional
manner.
Message creation will be described with reference to a sequence of
screen layouts in FIG. 8. In the initial screen for message
creation, the operator enters the first letters of the name of the
pager owner to whom the message is to be sent. The microprocessor
40 responds by searching through the pager file for each record
satisfying the search criteria and displays a first record. The
operator has the option of scrolling upwardly or downwardly through
a list of the located records. It is assumed, however, that first
record located, that of John Brown, identifies the desired pager.
The operator then presses the enter key of the keyboard 16 to
select the relevant pager. The operator is then presented with the
option of selecting several functions, namely paging, printing the
relevant user's stored messages, or viewing the messages for the
selected pager that are in a message queue 50 in SRAM 44. To create
a message, the operator selects the paging option. The operator is
then presented with a screen allowing entry of the required
message. Pressing the enter key causes the message to be recorded
in the message queue 50. The particular message generated is
identified with reference label M6 in FIG. 10.
The message M6 is actually stored as a record containing not only
the text of the message, but also status data and transmission
control data. The message record structure is illustrated in FIG.
6. The message record may include the following fields: a pager ID
field, a service field, a status field, a link field, a
transmission date field, a transmission time field, an error
message field, and a message field. The pager ID field contains the
actual pager number used by a paging service. With respect to
creation of the message M6, that data is automatically generated
and recorded in response to the user's selection of the pager user.
The service field contains the sequence number of the record in the
service file of the paging service associated with the pager. That
data is automatically generated from the corresponding field in the
selected pager record. The status field can contain various numeric
values, which may indicate the following message statuses: pending,
sent, cancelled, or rejected. The pending status indicates a
requirement for transmission. The sent status indicates that a
message has been transmitted to an associated paging service. The
cancelled status indicates that the operator has requested
cancellation of transmission. The rejected status is recorded by
the microprocessor 40 in response to a transmission error. The
microprocessor 40 automatically sets the status to pending upon
creation of the record. Each message when created is automatically
flagged for transmission, which is a preferred form of operation,
but not absolutely necessary. The link field is initially empty
(zero-value), but will later contain a pointer to the address in
SRAM 44 of the next message record created. The transmission time,
date and error fields are left temporarily empty. The
microprocessor 40 also updates the link field of stored message M5
to point to the address location of the new record M6.
The message queue 50 is maintained in accord with conventional
concepts regarding linked lists. A predetermined address in SRAM 44
contains a queue pointer to the first message M1 in the queue 50.
As described above, each message contains a link field pointing to
the succeeding record in the queue 50. The last record M6 has a
null-value in its link field, indicating the end of the queue 50.
The records are naturally ordered according to time of
creation.
The microprocessor 40 is multi-tasking. It provides two separate
and concurrent modes of operation. One mode is operator-controlled
which includes creating messages and altering status data to effect
retransmission. The other mode is an automatic mode of operation
controlling transmission of messages. How such separate modes of
operation are coordinated to avoid conflicts will be discussed
below.
Transmission of messages will be described with reference to FIG.
10. FIG. 10 diagrammatically illustrates the message queue 50, the
microprocessor 40, the keyboard 16, the display 14, the modem 46,
telephone lines 52 connecting the modem 46 to three paging services
PS1-PS3, and pagers served by the services and identified as P11,
P12, P21, P22, P31 and P32. The numeric parts of the pager
references are two digits, the first digit corresponding to the
associated paging service. In each message record of FIG. 10, only
the communication control data (service and pager fields), the
status data, and the link field of each record is presented. The
data has been represented in a manner that highlights associations
between messages, pager and services, and would not actually be
stored in such form in the message records.
The microprocessor 40 scans the message queue 50 starting with the
first message M1, which is located with the queue pointer, and
proceeding to succeeding message records by relying on the relevant
link field data contained in each message record. The first message
M1 has a sent status and is consequently ignored. The
microprocessor 40 selects the first message record whose status
data indicates a pending status. In the sample queue 50 of FIG. 10,
that is message M2. The microprocessor 40 retrieves the data in the
pager service field of message M2, which identifies paging service
PS3 by the sequence number of its pager service record. In response
to that data, the microprocessor 40 retrieves from the paging
service file the record for the paging service PS3. In response to
the communication data contained in the paging service record, the
microprocessor 40 programs the modem 46 (baud rate, word length,
parity etc.) for communication with paging service PS3. The
microprocessor 40 then selects one of the telephone numbers
associated with the paging service. It causes the modem 46 to
transmit the selected telephone number over the telephone lines 52.
If a telephonic connection is created between the modem 46 and
paging service PS3, the microprocessor 40 initiates the appropriate
log-on and message transmission procedures, the instructions for
which may be contained in the EPROM 42. The microprocessor 40 then
causes the selected message M2 to be transmitted to paging service
PS3. The microprocessor 40 waits for the modem 46 to report a
standard acknowledgement of receipt of the message, and then
updates the status field to indicate a sent status, and enters the
time and date of transmission in the appropriate fields of message
M2.
In response to the creation of the telephone connection, the
microprocessor 40 enters a selective scanning mode. The
microprocessor 40 scans through the rest of the messages in queue
50 for other messages whose transmission control data identify
paging service PS3. In the hypothetical circumstances of FIG. 10,
it locates the newly created record M6. The microprocessor 40 then
causes the modem 46 to transmit the data associated with message
record M6 to the paging service PS3 during the same communication
session. Assuming that an acknowledgement of receipt of message M6
is received, the microprocessor 40 then updates the status of
message record M6 to indicate a sent status, and enters the date
and time of transmission, as before. Since the end of the queue 50
has been reached, the selective scan mode is discontinued.
The process of scanning through the message queue 50 from first to
last message record to locate messages requiring transmission is
then repeated. On the next scan, the message M2, whose status is
now "sent" (status change not illustrated) is ignored. The
microprocessor 40 encounters and selects message record M3, which
is the first message in queue 50 that has a pending status. The
paging service field of message M3 indicates paging service PS2. In
response to that data, the microprocessor 40 retrieves the
communication data for paging service PS2, and programs the modem
46 appropriately for communication with the particular pager
service. It also causes transmission of a telephone number for the
paging service PS2, and logs onto the pager service PS2. In
response to the successful creation of a telephonic connection with
paging service PS2, the microprocessor 40 enters its selective
scanning mode. First, it initiates transmission of the message M3.
Assuming an acknowledgement of receipt of the message M3 is
received from the paging service PS2, the status field and the
transmission date and time fields of message record M3 are updated
accordingly. The microprocessor 40 then continues its selective
scanning toward the end of the message queue 50, searching for
other messages associated with paging service PS2 and having a
pending status. It locates message M5, satisfying those criteria.
The message M5 is then transmitted to paging service PS2 in a
similar manner, with appropriate updating of its status,
transmission date and transmission time fields. The scanning of the
message queue 50 is thereafter continually repeated, but no
messages with a pending status would be found and no transmission
would be initiated, until either a new message is appended to the
queue 50 or the status data associated with an existing message in
the queue 50 is appropriately changed.
The paging device 10 is also adapted to handle a busy signal
arising with attempts to create telephonic connections with a
particular service. If a busy signal is detected by the modem 46,
the modem 46 disconnects from the telephone line and reports the
busy signal to the microprocessor 40. The microprocessor 40 then
retrieves the data in the second telephone number field in the
paging service record associated with the particular paging
services, programs the modem 46 for transmission using the
alternative line of the paging service, and causes the modem 46 to
transmit the second number. It repeats these steps a predetermined
number of times, as set in the general communication data. This
repetitive process is terminated earlier if a telephonic connection
is established between the modem 46 and the particular paging
service.
Occasional transmission errors are to be expected. These may be
characterized as general communication errors and a
message-specific error (improper pager identification). Generally
communication errors include absence of a dial tone, busy signals,
and telephonic disconnection during transmission which is referred
to herein as a "hang-up" condition. A hang-up condition can be an
actual "HANG-UP" message (code according to IXO TAP protocols) from
the paging service, indicating its intention to voluntarily break a
telephonic connection, owing to some operational problem
encountered by the paging service. A hang-up condition can also be
created by the telephone system coupling the paging device 10 to a
paging service, a temporary disruption of the telephonic
connection. As regards individual messages, a number of messages
are potentially return by a paging services. Transmission of an
improper pager identification code is normally acknowledged with an
"RS" (Reject System) message, coded according to IXO TAP protocols.
Improper receipt of a message is generally acknowledged with a
"NACK" (No Acknowledgment) message, basically requesting
re-transmission. NACK messages are generally repeated a fixed
number of times, and if transmission of a pager message still
cannot be effected, a paging service will transmit a Hang-Up
message, discontinuing the communication session. The remaining
alternative is an "ACK" message, acknowledging receipt of a
message. The operation of the paging device 10 can of course be
modified to accommodate different protocols for handling and
acknowledging messages.
General communication errors affect the automatic mode of the
microprocessor 40 regulating transmission as follows. If the
problem arises before a telephonic connection can be completed
(e.g. no dial tone, repeated busy signals or repeated absence of a
carrier), the microprocessor 40 in its automatic mode of operation
changes the data of the currently selected message record to a
rejected status, and stores the error message returned by the modem
46 (no dial tone, no carrier or busy signals) in the error message
field of the affected message record. It does not enter its
selective scanning mode, but proceeds to locate the next record
whose status is pending and continues the general transmission
process described above. On subsequent scans of the message queue
50, any record with a rejected status is skipped. If a general
communication error arises subsequent to creation of a telephonic
connection (e.g. a hand-up message or condition), the
microprocessor 40 simply attempts to connect again to the
particular service and to transmit the currently selected message,
rather than assigning a rejected status and proceeding to the next
record in the queue 50.
A message-specific problem error is handled essentially as follows.
The microprocessor 40 will already have completed a telephonic
connection and will have entered its selective scanning mode. If
transmission of the message record currently selected for
transmission results in an RS message, probably reflecting an
improper pager identification code, the status field of the message
record is set to identify a rejected status and the error message
returned by the paging service is recorded in the error field.
Optionally, and preferably, an error message may be drawn
immediately to the attention of the operator to allow resetting of
the status of the message. The microprocessor 40 remains in its
selective scanning mode, proceeding through the rest of the message
queue 50 to locate another message requiring transmission to the
particular paging service.
The overall process of handling transmission in the automatic mode
of operation and accommodating transmission errors is shown in flow
chart form in FIGS. 11a-11c. A number of matters respecting the
flow chart should be noted. The starting point of the process has
been identified with an oval box containing the word "START". Other
"jump to" or continuation points in the procedure have been
identified in a similar manner. Procedure branches that return to a
jump-to point or proceed to a continuation point are terminated
with circular boxes identifying the relevant point in the
procedure. Rectangular boxes indicate operations and value
assignments, and rhomboid boxes indicate testing of conditions ("IF
statements"). All operations are performed on or with the currently
selected paging message record, paging service record, or retrieved
service telephone number. The "next message" in queue 50 when
commencing from the start of the procedure is the first message in
queue 50, as indicated by the queue pointer, if such a message
exists. A null queue pointer indicates that no messages are in
queue 50. Handling of busy signals and absence of a carrier have
been shown as a common type of operation to reduce the size of the
flow chart. A separate and substantially identical routine may be
used in connection with the handling of absence of a carrier, to
permit separate error messages to be generated for repeated busy
signals and repeated carrier failures. HANG-UP messages, after
log-on, are treated essentially as absence of a carrier signal.
Rejected messages are preferably drawn immediately to the
operator's attention. Rejected message may be immediately
displayed, in succession, including the message in its error field
identifying the nature of the communication error. The operator may
be constrained to enter, or given the option of entering, keyboard
commands that immediately change the status of each affected
message to either cancelled or pending. The latter would be
appropriate, for example, where the reported transmission error is
repeated busy signals or repeated inability to obtain a carrier
from the paging service. Lack of a dial tone is preferably reported
to the operator as a separate message before displaying rejected
messages, advising the operator to check the connection of the
paging device 10 to its associated telephone lines 52.
The operator can with appropriate commands retrieve and display on
the LCD 14 any message in the message queue 50. This is graphically
represented in FIG. 10, and screen layouts for message viewing and
status modification are shown in FIG. 12. The message M4 is
retrieved and reviewed. The message M4 is associated with pager
P12, which is assumed to be in the possession of a hypothetical
user, Susan Green. The operator can at his option reset the status
of the message M4 to a pending status, to initiate
re-transmission.
A screen of screens for message viewing and status changing is
shown in FIG. 12. The initial screens correspond to those for
message entry, leading to the screen offering paging, viewing and
printing options. The operator enters the letter "V" to trigger
message retrieval for the selected pager user Susan Green, pager
P12 of FIG. 10. The microprocessor 40 scans the queue 50 to select
all messages addressed to the selected pager. The operator can then
scroll through the selection of messages using the next and
previous keys. The operator may then select, for example, the
message record M4. The status of each message may be indicated with
single character symbols. For example, "X" may indicate a pending
status; "*", a sent status; and ".cent.", a cancelled status. The
operator can then alter the current status with a predetermined
command such as the combination of the keyboard's control key and
the letter "T". If the status is "cancelled" (as illustrated in
FIGS. 10 and 12) or "sent", the microprocessor 40 presents a screen
layout effectively asking for confirmation to change the status to
"pending" (for re-transmission), as illustrated in FIG. 12. If the
status of the record is "pending", the microprocessor 40 responds
by presenting screens asking in an analogous manner for
confirmation to change the status to "cancelled" (not illustrated).
If immediate processing of rejected messages is not required, then
a single character code for a rejected message can be displayed,
and the rejected message can be processed in a manner similar to
cancelled or sent message records. The operator is not permitted to
change the status of a pending message to sent or rejected. In
response to operator specification of a new status, the
microprocessor 40 alters the status data associated with the
message M4 accordingly.
Messages in the queue 50 will ultimately have to be deleted to free
SRAM for new messages. The automatic mode of operation regulating
transmission may be interrupted for record deletion. Any message
record may be deleted from the queue 50 by appropriately changing
the link field of a preceding message record to point to the
address in SRAM 44 of the immediately succeeding record. If the
first message record is to be deleted, the SRAM address pointing to
the first message record is simply to changed to point to the
second message record. If the last message in the queue 50 is to be
deleted, the link field of the second last record is simply voided.
Locations for new records can be assigned using conventional
techniques for locating free blocks of memory sufficient to accept
the new records.
The basic functions of the automatic and operator-controlled mode
of operation are integrated through the status fields associated
with the queued messages. In the automatic mode of operation, the
microprocessor 40 repeatedly scans the message queue 50 from
beginning to end, effectively acting on the status data of each
message record and updating the status data as transmissions are
attempted. The operator-controlled mode does not immediately
initiate or suppress transmission of messages. The operator in
essence changes status data associated with the queued messages,
allowing the automatic mode of operation to react accordingly. The
last step in storing a new message is updating the link field of
the last message in the queue 50 to point to the new message.
Simultaneous read and write operations to SRAM 44 by the two
concurrent procedures can be avoided with conventional multitasking
techniques. If a new message is added while the last message in
queue 50 is being processed for potential transmission, then
depending on when the link field of the last message is read in the
automatic mode, the new message will be immediately processed or
the repeated scanning of the message queue 50 will begin again with
the first message then in queue 50.
Communication data in the SRAM 44 of the paging device 10 can be
reconfigured, remotely over telephone lines 52, by a service center
54 which has a substantially identical device 56. The physical
arrangement for such servicing is illustrated in FIG. 13. The
paging device 10 has particular data-transmitting and
data-receiving modes for such purposes. The identical paging device
56 at the service center 54 of course has similar modes of
operation. These modes of operation will be discussed below in the
context of actual remote servicing of the paging device 10.
As a preliminary step, the service center device 56 is placed in
the data-receiving mode. The screen sequences used to initiate that
mode of operation and complete receipt of data are illustrated in
FIG. 15, and the procedure followed at the service center 54 is
indicated in the flow chart of FIG. 18. From the initial screen
layout configured for message creation, a command code is entered
by an operator at the keyboard of the service center device 56,
specifically, "@Clear", which conditions the microprocessor 40 of
the service center device 56 to clear all messages and
communication data from its SRAM. It presents a confirmation screen
and in response performs the deletion. Deletion of messages is the
primary purpose of this operation. The operator then enters a
predetermined command, specifically "@ANSWER", and the
microprocessor 40 assumes its data-receiving mode. The modem
associated with the service center device 56 is appropriately
programmed and its microprocessor 40 conditioned to await a
telephonic connection to be initiate by the user's paging device
10.
The user's paging device 10 is placed in its data-transmitting
mode. The screen sequences for such data transmission are shown in
FIG. 16, and a flow chart of the underlieing procedure is
illustrated in FIG. 17. Starting with the initial message entry
screen for message creation, the user enters a predetermined
command, such as "@CALL". The microprocessor 40 then presents a
screen layout prompting entry of a telephone number. The telephone
number for the service center device 56 is then entered. Upon
pressing the enter button, the microprocessor 40 causes the modem
46 to create a telephonic connection with the service center device
56. That involves transmitting the telephone number of the service
center 54 and performing customary hand-shaking. The necessary
communication protocol (log-on procedures, baud rate, parity, etc.)
for such service communication is preprogrammed and contained in
the EPROM 42. Once the connection is made, the microprocessor 40 of
the user's paging device 10 retrieves the communication data from
its SRAM 44 and transmits the communication data according to a
predetermined communication protocol, such as XMODEM with error
checking. First, it transmits an indicator indicating that it is
beginning transmission of block A of SRAM 44, its paging service
file. It then transmits the data contained in block A sequentially
from the starting address A. The service center device 56 responds
to the indicator by commencing writing the received data
sequentially to its corresponding SRAM block A starting at the
corresponding address A. The user's paging device 10 then transmits
an indicator indicating that it is beginning to transmit block B of
SRAM 44, its pager file. Once again, it transmits the data
contained in its block B sequentially from the starting address B.
The service center device 56 responds to the indicator by
commencing writing the received data sequentially to its
corresponding SRAM block B at address B in its SRAM. A screen may
be presented that adds a succession of characters such as "+" to
indicate to the user progress in data transmission.
Programming of the general communication functions required for the
data-receiving and data-transmitting modes is largely conventional
matters. However, the following aspects are to be noted. First, for
each of the paging service and pager files, the entire fixed-length
block of SRAM dedicated to the file is transmitted, including empty
memory locations. The data is transmitted beginning at the starting
address of the relevant block sequentially to the end of the block.
At the service center device 56, the data is sequentially rewritten
to identical SRAM blocks beginning at the same starting addresses
as in the user's paging device 10. Basically, a mirror-image of the
data files in the user's paging device 10 is reconstructed in the
service center device 56 at identical memory addresses, as
indicated in FIG. 14. The service center device 56 is immediately
conditioned to operate on the received communication data.
If the user has reported, for example, an inability to communicate
with a new paging service, the service center 54 can use the
procedure described above regarding data entry and editing of
service data information to check the specified communication
protocol with the service center device 56. Corrections can be
made, for example, to faulty baud rates, parity, word length, or
like matters. The communication protocol can be checked by
attempting transmission to the particular paging service,
addressing known pagers, for example, actually within the service
center 54. Similarly, if the user does not want to enter paging
service data for a new service, this can be done with the service
center device 56, augmenting the received data. Similarly, data
entered for a pager can be checked and corrected.
Once the received communication data is reconfigured, the
data-transmission modes of the two paging devices are reversed.
This will normally be coordinated by voice communication. First,
the communication data in the user's paging device 10 is cleared
following the procedure described above. Then the user's device 10
is placed in its data-receiving mode, awaiting a call from the
service center device 56. The service center device 56 is then
placed in its data-transmitting mode, following the procedures
described above. The telephone number for the user's paging device
10 is entered in the service center device 56, which then transmits
the telephone number and creates a telephonic connection with the
user's paging device 10. The service center device 56 then
transmits the reconfigured communication data to the user's paging
device 10, which assembles a mirror-image of the reconfigured data
at the appropriate memory locations in its SRAM. The user's device
10 is then configured for immediate communication. This arrangement
very significantly reduces service costs and down-time for the
user's paging device 10.
A similar procedure can be followed to transfer communication data
from the paging device 10 to the substantially identical paging
device 30 shown in FIG. 2. The RS-232 ports of the devices are
simply connected with the null modem adaptor 28, and telephonic
connection is unnecessary.
Communication data is of course stored in SRAM. A back-up power
supply may be provided to preserve the data during power failures,
but it is advisable to store a relatively permanent copy. To that
end, the data-transmitting and data-receiving modes may be adapted
to transmit and receive data via the RS-232 port 24 to a storage
device. That may be a disk drive itself, or the personal computer
26 as illustrated in FIG. 1 which will normally being associated
with a disk drive. Except that telephonic connection are not
required, the procedures involved are analogous to those described
above for transmissions to and from service center 56. The
conventional data transfer protocols appropriate for data transfer
to a disk drive or personal computer 26 are observed. A data file
is created in the storage device which is essentially a mirror
image of the data blocks dedicated to the paging service and pager
files. No attempt is made, however, to locate the data at any
particular starting address in the storage device, as the storage
device will not normally be adapted to process the received data.
During transfer of the stored communication data back to the paging
device 10, its SRAM blocks containing its paging service and pager
files are first cleared. The data in the stored device is retrieved
sequentially in the same order as originally transmitted, and
written sequentially to the SRAM blocks containing the paging
service and pager files.
It will be appreciated that particular embodiments of the invention
have been described and that modifications may be made therein
without departing from the spirit of the invention or necessarily
departing from the scope of the appended claims.
* * * * *